1. Field of the Invention
This invention relates to a method and an apparatus for separating and recovering mercury from the mercurial "soot" condensed following the roasting of mercury ore. The mercurial "soot" is a mixture of fine globules of mercury (floured mercury), ore dust, mercury salts, ashes, tar and other condensation products, possibly arsenic and antimony compounds, and water. Soot may contain 20 - 85% mercury. Mercury recovered from the separator following the lime treatment there is stored to await shipment.
2. The Prior Art
Conventional methods of treating "soot" for separation of mercury comprise hoeing, with or without the addition of lime and application of heat, burning, pressing in pans with stirrer or rollers, or heating under vacuum. Some of the methods produce relatively less yields of mercury, and industrial hygiene is a problem. Difficulties are encountered with adequate separation of the mercury in the soot treatment and with the subsequent handling of the treated soot prior to and at the roaster.
Moreover, in at least one operating mercury plant, previously it had been necessary to re-pulp the treated soot with water and pump it out to storage and then re-lime the treated soot before returning it to the roaster. The present invention avoids these difficulties in not having to re-pulp the treated soot before returning it to the roaster thus reducing lime consumption in the order of about 20%. Moreover, operating time per batch is virtually cut in half.